It's not indefinite. The longest lockdown in China was 76 days, in Wuhan. Elsewhere, it was significantly shorter. Because they had a strict lockdown early on, they have been living with far fewer restrictions than most of the world for about a year now.
> the virus is only going to pop back up.
It does indeed pop up every once in a while, because the borders can never be 100% sealed. There have been outbreaks in Beijing, Qingdao, border towns in Heilongjiang and Yunnan, and elsewhere. But the government is understandably on high alert, and these outbreaks were caught early enough to be stopped with local lockdowns, coupled with blanket testing of the population (i.e., testing everyone in a city in a few days).
There was a brief "second wave" in China this winter, in which an outbreak managed to spread to several cities, but it was ended with relatively short lockdowns and mass testing. The number of new infections per day peaked around 100.
The basic lesson here is that you can both have near-zero case counts and let people live their lives almost as normal if you first act decisively to bring cases to zero, by using temporary, strict lockdowns, quarantines and mass testing.
> There is no evidence of such a strategy working at scale across the world.
China is the largest country in the world, so I'd call that "at scale." Vietnam is larger than any EU country. We're not talking about San Marino or Monaco here.
> The scientists on the covid team at the WHO have said as much: lockdowns should only be used as a last resort to buy time to scale up health care resources. Should we listen to those scientists?
A lot of recommendations will be reevaluated after the pandemic is over. Nothing like this has happened in 100 years.